@@ -2,27 +2,27 @@ package main
 
 import (
 	"fmt"
-	"log"
 	"sync"
 
 	"github.com/hashicorp/serf/serf"
+	"golang.org/x/exp/slog"
 )
 
 // Agent starts and manages a Serf & adds service discovery (TODO)
 type Agent struct {
 	serfConf *serf.Config
 	eventCh  chan serf.Event
-
 	// This is the underlying Serf we are wrapping
 	serf *serf.Serf
-
+	// a lil logger used by the agent, you know how it be
+	logger *slog.Logger
 	// this channel receiving a signal = shutdown
 	shutdown     bool
 	shutdownCh   chan struct{}
 	shutdownLock sync.Mutex
 }
 
-func Create(serfConf *serf.Config) *Agent {
+func Create(config *Config, serfConf *serf.Config, logger *slog.Logger) *Agent {
 	// Create a channel to listen for events from Serf
 	eventCh := make(chan serf.Event, 64)
 	serfConf.EventCh = eventCh
@@ -31,6 +31,7 @@ // Setup the agent
 	agent := &Agent{
 		serfConf:   serfConf,
 		eventCh:    eventCh,
+		logger:     logger,
 		shutdownCh: make(chan struct{}),
 	}
 
@@ -42,10 +43,10 @@ serfShutdownCh := a.serf.ShutdownCh()
 	for {
 		select {
 		case e := <-a.eventCh:
-			log.Printf("[INFO] cascade: Received event: %s", e.String())
+			a.logger.Info("receive event", "event", e.String())
 
 		case <-serfShutdownCh:
-			log.Printf("[INFO] cascade: serf shutdown detected, quitting eventloop")
+			a.logger.Info("detect serf shutdown, turning off event loop")
 			a.Shutdown()
 			return
 
@@ -56,12 +57,12 @@ }
 }
 
 func (a *Agent) Start() error {
-	log.Printf("[INFO] cascade: Serf agent starting")
+	a.logger.Info("start serf agent")
 
 	// Create serf first
 	serf, err := serf.Create(a.serfConf)
 	if err != nil {
-		return fmt.Errorf("Error creating Serf: %s", err)
+		return err
 	}
 	a.serf = serf
 
@@ -84,13 +85,13 @@ if a.serf == nil {
 		goto EXIT
 	}
 
-	log.Println("[INFO] cascade: requesting serf shutdown")
+	a.logger.Info("request serf shutdown")
 	if err := a.serf.Shutdown(); err != nil {
 		return err
 	}
 
 EXIT:
-	log.Println("[INFO] cascade: shutdown complete")
+	a.logger.Info("complete serf shutdown")
 	a.shutdown = true
 	close(a.shutdownCh)
 	return nil
@@ -98,12 +99,12 @@ }
 
 // Join asks the Serf instance to join. See the Serf.Join function.
 func (a *Agent) Join(addrs []string) (n int, err error) {
-	log.Printf("[INFO] cascade: issuing join request to '%v'", addrs)
+	a.logger.Info("issue join request", "addrs", addrs)
 	// we always ignore old events because cascade don't
 	// care about the past
 	n, err = a.serf.Join(addrs, true)
 	if err != nil {
-		return n, fmt.Errorf("[ERR] cascade: error joining: %v\n", err)
+		return n, fmt.Errorf("Error joining: %v\n", err)
 	}
 	// TODO: when joining fails, we don't get an error here - serf & memberlist
 	// just print to stdout and serf.Join returns without issue.
@@ -116,7 +117,7 @@ if a.serf == nil {
 		return nil
 	}
 
-	log.Println("[INFO] cascade: requesting graceful leave from Serf")
+	a.logger.Info("request graceful serf leave")
 	return a.serf.Leave()
 }
 

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"net"
 	"os"
+
+	"golang.org/x/exp/slog"
 )
 
 const DefaultBindPort int = 4449
@@ -16,6 +18,7 @@ }
 
 	return &Config{
 		BindAddr: "0.0.0.0",
+		LogLevel: "INFO",
 		NodeName: hostname,
 	}
 }
@@ -30,6 +33,7 @@ }
 
 type Config struct {
 	BindAddr  string
+	LogLevel  string
 	NodeName  string
 	StartJoin []string
 	Services  []Service
@@ -57,3 +61,20 @@ }
 
 	return addr.IP.String(), addr.Port, nil
 }
+
+func (c *Config) GetLogLevel() slog.Level {
+	var lvl slog.Level
+	if c.LogLevel == "DEBUG" {
+		lvl = slog.LevelDebug
+	}
+	if c.LogLevel == "INFO" {
+		lvl = slog.LevelInfo
+	}
+	if c.LogLevel == "WARN" || c.LogLevel == "WARNING" {
+		lvl = slog.LevelWarn
+	}
+	if c.LogLevel == "ERR" || c.LogLevel == "ERROR" {
+		lvl = slog.LevelError
+	}
+	return lvl
+}

@@ -2,7 +2,11 @@ module git.j3s.sh/cascade
 
 go 1.20
 
-require github.com/hashicorp/serf v0.10.1
+require (
+	github.com/hashicorp/memberlist v0.5.0
+	github.com/hashicorp/serf v0.10.1
+	golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb
+)
 
 require (
 	github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da // indirect
@@ -13,9 +17,8 @@ github.com/hashicorp/go-msgpack v0.5.3 // indirect
 	github.com/hashicorp/go-multierror v1.1.0 // indirect
 	github.com/hashicorp/go-sockaddr v1.0.0 // indirect
 	github.com/hashicorp/golang-lru v0.5.0 // indirect
-	github.com/hashicorp/memberlist v0.5.0 // indirect
 	github.com/miekg/dns v1.1.41 // indirect
 	github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529 // indirect
 	golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1 // indirect
-	golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 // indirect
+	golang.org/x/sys v0.1.0 // indirect
 )

@@ -56,6 +56,8 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190923035154-9ee001bba392/go.mod h1:/lpIB1dKB+9EgE3H3cr1v9wB50oz8l4C4h62xy7jSTY=
+golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb h1:PaBZQdo+iSDyHT053FjUCgZQ/9uqVwPOcl7KSWhKn6w=
+golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@@ -77,6 +79,8 @@ golang.org/x/sys v0.0.0-20210303074136-134d130e1a04/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 h1:WIoqL4EROvwiPdUtaip4VcDdpZ4kha7wBWZrbVKCIZg=
 golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
+golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=

@@ -10,7 +10,6 @@ package main
 
 import (
 	"fmt"
-	"log"
 	"os"
 	"os/signal"
 	"strings"
@@ -19,6 +18,7 @@ "time"
 
 	"github.com/hashicorp/memberlist"
 	"github.com/hashicorp/serf/serf"
+	"golang.org/x/exp/slog"
 )
 
 const (
@@ -29,28 +29,42 @@ )
 
 func main() {
 	config := readConfig()
-	agent := setupAgent(config)
+	logger := setupLogger(config)
+	agent := setupAgent(config, logger)
 	if err := agent.Start(); err != nil {
-		log.Panic(err)
+		panic(err)
 	}
 	defer agent.Shutdown()
 	// join any specified startup nodes
 	if err := startupJoin(config, agent); err != nil {
-		log.Fatal(err)
+		panic(err)
 	}
-	if os.Getenv("CASCADE_DEBUG") != "" {
-		go debugPrints(agent)
+	go debugPrints(agent)
+	if err := handleSignals(config, agent); err != nil {
+		panic(err)
+	}
+}
+
+func setupLogger(config *Config) *slog.Logger {
+	debugOn := false
+	if config.LogLevel == "DEBUG" {
+		debugOn = true
 	}
-	if err := handleSignals(config, agent); err != nil {
-		log.Panic(err)
+	opts := slog.HandlerOptions{
+		Level: config.GetLogLevel(),
+		AddSource: debugOn,
 	}
+	handler := opts.NewTextHandler(os.Stderr)
+	logger := slog.New(handler)
+	slog.SetDefault(logger)
+	return logger
 }
 
-func debugPrints(agent *Agent) {
+
+func debugPrints(a *Agent) {
 	for {
-		for _, m := range agent.serf.Members() {
-			log.Printf("[DEBUG] cascade: name '%s' addr '%s' status '%s' \n",
-				m.Name, m.Addr, m.Status)
+		for _, m := range a.serf.Members() {
+			a.logger.Debug("debug-loop", "name", m.Name, "addr", m.Addr, "status", m.Status)
 		}
 		time.Sleep(time.Second * 5)
 	}
@@ -70,7 +84,7 @@ case <-agent.ShutdownCh():
 		// Agent is already shutdown!
 		return nil
 	}
-	log.Printf("Caught signal: %v", sig)
+	agent.logger.Info("caught signal", "signal", sig)
 
 	// Check if we should do a graceful leave
 	graceful := false
@@ -80,15 +94,16 @@ }
 
 	// Bail fast if not doing a graceful leave
 	if !graceful {
-		log.Fatal("[WARN] cascade: non-graceful leave detected")
+		agent.logger.Warn("leave cluster with zero grace")
+		return nil
 	}
 
 	// Attempt a graceful leave
 	gracefulCh := make(chan struct{})
-	log.Println("Gracefully shutting down agent...")
+	agent.logger.Info("shut down agent gracefully")
 	go func() {
 		if err := agent.Leave(); err != nil {
-			log.Printf("Error: %s", err)
+			agent.logger.Error("Error: %s", err)
 			return
 		}
 		close(gracefulCh)
@@ -97,9 +112,9 @@ 
 	// Wait for leave or another signal
 	select {
 	case <-signalCh:
-		return fmt.Errorf("[WARN] cascade: idk")
+		return fmt.Errorf("idfk")
 	case <-time.After(gracefulTimeout):
-		return fmt.Errorf("[WARN] cascade: leave timed out")
+		return fmt.Errorf("leave timed out")
 	case <-gracefulCh:
 		return nil
 	}
@@ -107,7 +122,11 @@ }
 
 func readConfig() *Config {
 	config := DefaultConfig()
-	// CASCADE_BIND=127.0.0.1:1234
+	// CASCADE_LOGLEVEL=info
+	if os.Getenv("CASCADE_LOGLEVEL") != "" {
+		config.LogLevel = strings.ToUpper(os.Getenv("CASCADE_LOGLEVEL"))
+	}
+	// CASCADE_BIND=192.168.0.15:12345
 	if os.Getenv("CASCADE_BIND") != "" {
 		config.BindAddr = os.Getenv("CASCADE_BIND")
 	}
@@ -132,19 +151,23 @@ if err != nil {
 		return err
 	}
 	if n > 0 {
-		log.Printf("[INFO] cascade: join request issued to %d nodes", n)
+		agent.logger.Info("issue join request", "nodes", n)
 	}
 
 	return nil
 }
 
-func setupAgent(config *Config) *Agent {
+func setupAgent(config *Config, logger *slog.Logger) *Agent {
 	bindIP, bindPort, err := config.AddrParts(config.BindAddr)
 	if err != nil {
-		log.Panic(err)
+		panic(err)
 	}
 
 	serfConfig := serf.DefaultConfig()
+	// logLogger is just a bridge from the old logger to the
+	// new slog handler.
+	logLogger := slog.NewLogLogger(logger.Handler(), config.GetLogLevel())
+	serfConfig.Logger = logLogger
 	serfConfig.NodeName = config.NodeName
 	serfConfig.ProtocolVersion = uint8(serf.ProtocolVersionMax)
 	// TODO: how should cascade handle name conflicts?
@@ -160,11 +183,12 @@ serfConfig.QueueDepthWarning = 1000000
 	serfConfig.ReconnectTimeout = 3 * 24 * time.Hour
 
 	serfConfig.MemberlistConfig = memberlist.DefaultWANConfig()
+	serfConfig.MemberlistConfig.Logger = logLogger
 	serfConfig.MemberlistConfig.DeadNodeReclaimTime = 30 * time.Second
 	serfConfig.MemberlistConfig.BindAddr = bindIP
 	serfConfig.MemberlistConfig.BindPort = bindPort
 
-	agent := Create(serfConfig)
+	agent := Create(config, serfConfig, logger)
 	return agent
 }